One main objective of our research is to determine the role of caltrin in the development of the sperm acrosome reaction and in the acquisition of fertilizing capacity. We wish to learn if caltrin is found in all mammalian seminal fluid and we intend to document the different mechanisms used by different species to convert the inhibitory form to a conformation that enhances calcium uptake by the spermatozoa. A second main objective is to discover the mechanism by which thermogenic hormones function. The enzymes that are induced by thyroid hormone and dehydroepiandrosterone can be assigned roles that result in decreased metabolic efficiency and increased heat production. Our task is to establish a pathway by which reducing equivalents generated by malic enzyme can be used to convert dihydroxyacetone phosphate to sn-glycerol 3-phosphate. A third, but lesser, objective is to study the role of exercise training in the adaptation of enzyme activity to cope with the increased production of toxic oxygen radicals.